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Perceptual Study and Auditory Analysis on Digital Crossover Filters

Digital crossover filters offer interesting possibilities for sound reproduction, but there does not exist many publications on how they behave perceptually. In this research, phase and magnitude errors in digital implementations of linear phase FIR as well as Linkwitz-Riley crossover filters are studied perceptually and by auditory analysis. In a headphone simulation listening experiment we explored the just noticeable level of degradation due to crossover filter artifacts. In a real loudspeaker experiment we explored rough guidelines for 'safe' filter orders of linear-phase FIR crossover filters, which would not produce audible errors. Possibilities to predict the perceived errors were then explored using auditory analysis, including also third-octave magnitude spectrum and group delay as simple auditory correlates. Linear-phase FIR crossovers were found to produce different kind of phase errors than Linkwitz-Riley crossovers. The auditory analysis can qualitatively explain the perceptibility degradation.